Conventionally, there were two methods for removing a resin joint or resin ribs:
(a) The resin joint was removed by pushing a minus screw driver into the gap between the pipe and the resin joint, or by using a saw or other cutting means to cut off the resin joint, if the joint was removed from the pipe having the joint adhered and fitted thereto at one end or at a middle point of the pipe, as in the cases of the pipe remaining after a structure had been disassembled or the pipe fitted with a resin joint at a wrong position; and PA1 (b) If resin ribs were removed from the cylindrical pipe having them formed on its surface, there had to be provision for various types of feed rolls and work coils which corresponded to the shapes of the resin ribs. These ribs were removed by transferring the feed rolls and the work coil in the axial direction, heating the ribs to soften them, and scraping them by a scraping means. PA1 (a) If a resin joint is removed from the pipe by inserting a minus screw driver to break the joint or by cutting the pipe with a saw, the pipe itself and the resin coating are damaged and they are spoiled aesthetically. It is difficult to measure the saw-cut pipe with high precision. Even if the saw-cut pipe is reprocessed, the pipe inevitably gets shorter in length and finds less opportunity for reuse. PA1 (b) If resin ribs are removed from pipe, there must be various types of feed rolls and work coils in response to the shapes of the resin ribs. Therefore, it takes much time to plan the work of removing (peeling) resin ribs from the pipe. Work is impossible with a single type of feed rolls and a single work coil. PA1 A fixed plate; a cylinder plate having a cylinder fitted perpendicularly to the outer surface thereof, said cylinder being fitted with a piston rod extending from said cylinder and passing through a hole opened in the approximately central area of said cylinder plate; a frame on which to mount said fixed plate and said cylinder plate, to connect them with each other by stay shafts at a given space apart and in the positions parallel to each other, and to fix them; and a moving plate disposed between said fixed plate and said cylinder plate, which is fixed to the tip of said piston rod in a manner horizontally moving along said stay shafts as said piston rod moves forward or backward; PA1 A lower clamp portion of a V-shape disposed on the upper central area of said cylinder plate to support the pipe portion of the pipe fitted with a resin joint or two; and a clamp provided in its lower area with an upper clamp portion of a reverse-V shape disposed right above said lower clamp portion and provided in its upper area with guide holes to make guide shafts pass through said holes in a horizontally movable manner, said clamp being fitted in a vertically movable manner to the tip of the piston rod of a cylinder vertically fixed to a cylinder mount vertically installed on said cylinder plate; and PA1 A V-shaped pipe support disposed in the upper central area of said moving plate, which together with said lower clamp portion, holds the pipe portion horizontally; a guide rod vertically disposed in proximity to said pipe support; a lower scraper mount fixed to the inner surface of said moving plate; a lower scraper in the shape of a lower half circle, such as obtained by horizontally dividing into two halves a circle with a bore slightly larger than the outer diameter of the pipe portion, said lower scraper being provided with blades fitted thereto, which are directed toward the fixed plate; and an upper scraper, i.e., the other half of the scraper, being disposed right above said lower scraper and facing it correspondingly and being fitted to an upper scraper mount in a manner vertically moving along the guide rod, said upper scraper mount being fixed to one ends of the guide shafts, with the other ends being allowed to pass slidably through the guide holes of the aforementioned clamp. PA1 A fixed plate; a cylinder plate having a cylinder fitted perpendicularly to the outer surface thereof, said cylinder being fitted with a piston rod extending from said cylinder and passing through a hole opened at a given position of said cylinder plate; a frame on which to mount said fixed plate and said cylinder plate, to connect them with each other by stay shafts at a given space apart and in the positions parallel to each other, and to fix them; and a moving plate disposed between said fixed plate and said cylinder plate, which is fixed to the tip of said piston rod in a manner horizontally moving along said stay shafts as said piston rod moves forward or backward; PA1 An extruding pin disposed in the approximately central area of said moving plate, with its conical head being directed horizontally toward said cylinder plate; PA1 A pipe hole being open in said cylinder plate at a position opposite to said extruding pin and having a bore slightly larger than the outer diameter of the pipe portion; and a scraper provided with a circular opening and disposed on the inner surface of said cylinder plate, said opening having a bore roughly identical with the bore of said pipe hole, with a cutter being disposed coaxially with the pipe hole and directed toward said extruding pin; PA1 A fitting plate fixed to the outer surface of said cylinder plate in its upper area so that about a part of said fitting plate is projected upward from the top edge of said cylinder plate; a piston rod hole being open in said projected area; a cylinder disposed perpendicularly to the inner surface of said fitting plate and provided with a piston rod which is horizontally movable in the outward direction through said piston rod hole; guide pins fitted to the outer surface of said fitting plate in parallel to the direction in which said piston rod moves forward or backward; a support plate disposed next to and on the outside of said fitting plate and having guide pin holes in the upper area of said support plate to allow said guide pins to pass through; a centering pin fixed perpendicularly to the lower area of said support plate so that said pin can be passed through the pipe hole, with the conical pin head directed toward the extruding pin; and a slider provided with a slide roller and fixed perpendicularly to said support plate which, in turn, is fitted rotatably to the tip of said piston rod; and PA1 A guide plate disposed on the outer surface of said cylinder plate and organized by a straight groove which is engaged with said slide roller to enable said centering pin to be moved linearly inside said groove and guided in the axial direction of said pipe hole, and by an escape groove which is used to make said centering pin get out of the passageway of the pipe in parallel to the axial direction of said pipe hole. PA1 A fitting plate disposed in such a way that a part of said fitting plate is projected horizontally from the side edge of said cylinder plate and fixed at its overlapped base area to the outer surface of said cylinder plate; a piston rod hole being open in the area of the fitting plate that is projected from the edge of the cylinder plate; a cylinder installed perpendicularly to the inner surface of said cylinder plate and provided with a piston rod which passes through said piston rod hole and extends outward in a manner horizontally moving forward or backward; guide pins disposed on the outer surface of said fitting plate in parallel to the direction in which said piston rod moves forward or backward; a support plate fitted on the outside of said fitting plate in proximity and parallel thereto; and a guide plate fixed perpendicularly to the outer surface of said cylinder plate, with said escape groove turning upward.
However, these conventional methods have the following problems: